A conventional touchscreen registers touch events when a user's finger or a physical object held by a user, such as a stylus, comes into contact with the surface of the touchscreen. Conventional touchscreens have many advantages and are becoming commonplace in computers, mobile devices, and other consumer electronic devices, etc. However, in some use environments, it may be desirable to have a touchless gesturing input system instead of a conventional touchscreen. A touchless gesturing input system is capable of capturing a user's hand gestures, hand movements, or the movements of a physical object held by a user, etc., without the user's hand or the physical object coming into contact with the touchless gesturing input system itself. With such a touchless gesturing input system, a user may interact with an electronic user interface by making specific hand gestures or movements, or by moving some physical object in a particular way. In some embodiments, a touchless gesturing input system may be integrated with a display device so that a user may intuitively manipulate elements of a user interface displayed on the display device by making hand gestures or other movements in front of the display device.
Some suitable lensless imaging systems for use as touchless gesturing input systems are known in the art. For example, such a lensless imaging system may be comprised of a substrate, an array of reflective features formed with a substantially even distribution on or in the substrate, and a plurality of photodetectors provided on the edges of the substrate. A suitable routine is also implemented with the lensless imaging system. When the lensless imaging system is in operation, incident ambient light from the front side of the substrate is reflected off of the reflective features toward the photodetectors. Then the routine processes the signals generated by the photodetectors to obtain a rough image of the object(s) in front of the lensless imaging system.
For example, the substrate of a lensless imaging system may be transparent and oblong rectangular, and is of the same length and width as or of slightly longer length and width than a regular flat screen display on which the lensless imaging system is superimposed. When a user moves a hand or an object in front of the lensless imaging system, successive corresponding images are generated by the lensless imaging system. Combined with proper software, such a combination of the lensless imaging system and the flat screen display allows a user to manipulate elements of a user interface displayed on the flat screen display by making hand gestures or movements, or by moving some other object, in front of the lensless imaging system.
Different shapes of the reflective features and/or distributions of such reflective features over a surface for receiving ambient light may be used in a lensless imaging system. The shape of the reflective features used may impact the quality of the images obtained, and therefore shapes of the reflective features that result in images of higher quality are desirable.